imac itunes files not showing on PS3

[gen666]

I am using PS3 media server on an imac and macbook, uneventfully, that is until now.

Everything is still working fine with my macbook but, out-of-the-blue the PS3 says "There are no titles" when you go into the movie or music on the PS3. The itunes contains a mixture of purchased and burned files. I have played around without success (I had tired to locate and the itunes folder and the whole hard disk to the server but this only showed 2 movie files on PS3!) I feel rather dumb...any ideas? Thanks.